Provided is an antibody or fragment thereof comprising a V L domain wherein the V L domain comprises three CDRs wherein the sequence of CDRI is a specified amino acids sequence or a sequence at least 70% identical thereto, and the sequence of CDR3 is a specified amino acid sequence or a sequence at least 70% identical thereto and wherein the antibody or fragment thereof binds Colo205 cells. The antibody can be used to treat tumours.